Chemotherapy works by killing rapidly dividing cancer cells. As it wipes out cancer cells, though, chemotherapy can also destroy fast-growing healthy cells. This may cause you to experience side effects.

Lower blood cell production

Your bone marrow's ability to make blood cells might decrease.

Anemia. You may not have enough healthy red blood cells to carry oxygen to your tissues, which can leave you feeling tired or short of breath.

Bleeding. You may not have enough platelets — a blood cell that plays an important role in forming blood clots — to help prevent bleeding when you're injured.

Infections. You may make fewer white blood cells, which protect your body from infections. An elevated body temperature may be the earliest sign of an infection.

Gastrointestinal symptoms

The lining of your stomach and intestines could become damaged.

Diarrhea. Your body's ability to absorb nutrients from food and get rid of waste might be affected.

Nausea and vomiting. Damage to your stomach and intestinal lining can also cause nausea and vomiting.

Constipation. Though less common, constipation also can be a side effect of chemotherapy.

Skin and hair symptoms

Hair loss. This happens most often on the scalp but your eyebrows and eyelashes may thin, too. Fortunately, hair loss is almost always temporary.

Mouth sores. Damage to the cells in your mouth can create sores that make it difficult to eat and drink.

Whole-body effects

Chemotherapy drugs go through your bloodstream and can affect your whole body. That can cause symptoms such as fatigue. Feeling tired or having little energy is a common side effect of many types of chemotherapy.

Work with your health care team

Consider preparing a list of questions about side effects to ask your health care team so that you can get ready for chemotherapy.

Here are some questions you can ask:

What side effects are most common with the drugs I'm receiving?

How do these compare with the side effects of other treatments?

What can I do to prepare for these side effects?

What can I do to decrease the chances that I'll have them?

What side effects are dangerous and should prompt a call or visit to the clinic?

May I call you anytime if I have these side effects? What phone number should I use?

After you start treatment, it's important to tell your health care team about all the side effects you experience. The earlier they know, the more likely they can prevent side effects from becoming more-serious problems.

Learning you have breast cancer can come as a shock. After coping with the initial diagnosis and gathering support from your loved ones, there are questions you should ask your cancer-care team to make sure you are getting the information you need.